Hydraulic locking device with stroke adjusting means



April 13, 1965 P. PORTER 3,177,980

HYDRAULIC LOCKING DEVICE WITH STROKE ADJUSTING MEANS Original Filed March l0, 1959 2 Sheets-Sheet l br Z N w? .4 w/ l M NN/ M WAN N Q @MN Nm. I l. v\V.\\/,//////w\-, llt. l MV l, f m 1 f /zwm N u l H fm w, m x .rf ummm MNIR wimw m 3% mi QN. QNMN wk I Nw ww f e R lum. 1, si Wav Q l@ Sv ww. NN E Nm uw ww April 13, 1965 P. L. PORTER 3,177,980

HYDRAULIC LOCKING DEVICE WITH STROKE ADJUSTING MEANS original Filed March 1o, 1959 2 sheets-sheet 2 @War/7545 United States Patent O 3,177,980 HYDRAULIC LOCKING DEVICE WITH STRGKE ADIUSTING MEANS Percy L. Porter, Los Angeles, Calif., assigner to P. L. Porter Co., Los Angeles, Calif.

Original application Mar. 10, 1959, Ser. No. 798,436, now1 Patent No. 3,051,274, dated Aug. 2S, 1962. Divided and this application Jan. 11, 1962, Ser. No. 165,613

4 Claims. (Cl. 18S-96) This invention relates to a longitudinally extensible and contractible hydraulic locking device to control the spacing between two members and is a division of my copending application Serial No. 798,436 tiled March 10, 1959, now issued as Patent 3,051,274. While the invention is widely applicable for its purpose, it has special utility for controlling the tiltable back rest of a reclining seat for use in aircraft and other vehicles. Such an ernbodiment of the invention has been selected for the present disclosure and will provide adequate guidance for those skilled in the art who may have occasion to apply the same principles to other specific purposes.

A device of this type is disclosed in the Porter et al. Patent 2,559,047 issued July 3, 1951, and the application of such a device to the control of a tiltable back rest of a reclining chair is set forth in the Armstrong Patent 2,522,246, issued September l2, 1950. These two prior disclosures are hereby incorporated in the present disclosure by reference.

A hydraulic locking device of this type comprises a cylinder coniining a quantity of hydraulic uid and a piston dividing the cylinder into two hydraulic locking chambers, the piston being unitary with a tubular piston rod which extends through both ends of the cylinder. What may be termed a locking valve controls communication between the two locking chambers and is normally closed to immobilize the piston. A heavy external coil spring functions in compression between the cylinder and the piston rod to oppose contraction of the hydraulic locking device, i.e., to oppose the backward tilt of the back rest of the seat. 'Ihus the heavy spring serves to counterbalance and to erect the back rest.

Space inside the tubular piston rod is utilized as a reservoir in communication with one of the two hydraulic chambers to hold a reserve supply of the hydraulic fluid. This reservoir is adapted to expand and contract to accommodate thermal expansion and contraction of the structure and of the fluid in the two locking chambers.

The problem to which the present invention is directed arises from the fact that the seats in an airplane are mounted on a longitudinal track which makes it possible to remove seats and add seats at will for various types of service. For so-called high density seating, the seats are placed close together, for example for daytime coach service. The sea'ts are more widely spaced for rst-class daytime service to permit the back rests to be tilted backward to substantial angles. Still fewer seats at greater spacing are employed for night ying to permit the back rests to be tilted to the maximum angles. The problem is to provide seats which may be used interchangeably for these various kinds of services without the possibility of a back rest being tilted by an occupant to a greater angle than permitted by the spacing oi the seats, with consequent hazard to the occupant of the next rearward seat.

The invention meets this problem by providing for adjustability of the maximum length of the stroke of the hydraulic locking device. The maximum length is selected for maximum spacing of the seats, an intermediate length is used for intermediate spacing of the seats, and a third shorter lenvth adjustment is available for use when the seats are at minimum spacing. This feature makes the seat highly liexible in the sense that it may be readily adapted to the various kinds of service.'

The features and advantages of the invention may be understood from the following detailed descriptiontaken with the accompanying drawings.

In the drawings, which are to be regarded as merely illustrative:

FIG. 1 is a side elevation of the presently preferred embodiment of the invention;

FIG. 2 is an enlarged longitudinal sectional view of the same embodiment of the invention;

FIG. 3 is an enlarged fragmentary longitudinal sec tional view showing the construction of the gland of the iiuid reservoir; and

FIG. 4 is a similarly enlarged fragmentary longitudinal sectional view of the piston assembly including the locking valve and the check valve.

General arrangement The principal parts of the embodiment of the invention shown in FIGS. 1 to 4 include: a cylinder 16 with two end walls 12 and 14; a tubular piston rod 15 extending through the two end walls; a piston 16 united with the piston rod and dividing the interior of the cylinder between the two end walls into two locking chambers 1S and 20; a heavy external counterbalancing coil spring 22 in compression between the cylinder and the piston rod to exert counterbalancing force; a locking valve in the form of a ball member 24 seating in the piston 16 to control tiuid flow between the two locking chambers through the piston; a check valve inside the tubular piston rod in the form of a solid cylindrical valve member, generally designated 25 (FIG. 4) with a tapered shoulder for normal pressure contact with a seat in the form of an O-ring 26, this cylindrical valve body extending to the locking valve ball 24 for actuating thereof; a coil spring 27 acting under compression normally to hold both the locking valve ball member 24 and the check valve member 25 in their closed positions; a tubular gland, generally designated 28, under the pressure of a coil spring 30 to serve as one end wall of an annular fluid reservoir chamber 32, the second end wall of the chamber being provided by the check valve; an operating rod or push rod 34 extending from the exterior or" the device through the gland 28 and through the G-ring 26 into a socket 35 (FIG. 4) ofthe check Valve member 25 to shift the check valve member towards its open position and thereby unseat the locking valve ball member 24; cam means 36 cooperating with a follower in the form of a diametrical pin 38 to convert rotation of the operating rod 34 into longitudinal shift thereof to operate the two valves; means to prevent relative rotation between the cylinder 1t) and the piston rod 15 comprising a pair of diametrically opposite longitudinal slots 4t) (FIG. l) in an extension 42 of the cylinder and a diametrical pin 44 that is carried by the piston rod in sliding engagement with the two slots; an adjustable stop sleeve i5 (FIG. l) that is rotatably mounted on the cylinder extension `52 and has a pair of diametri'ca'lly opposite slots 46 of stepped configuration providing corresponding pairs of stop shoulders 48, 50 and 52 to cooperate selectively with the diametrical pin 44; and detent means 54 (FIG. 2) to releasably hold the stop sleeve 45 selectively at three positions for cooperation of the stop shoulders 4S, 50 and 52, respectively, with the diametrical pin 44. The detent means 54 shown in FIG. 2 is in the form of a steel ball under radial pressure by a spring 102. The inner circumference of the stop sleeve 45 has a series of three longitudinal grooves 194 for selective `engagement by the detent ball, the positions of the longitudinal :grooves corresponding to the effective positions of the stop shoulders 48, 50, and 52.

Y Operation FIG. 1 shows how a threaded extension '76 of the tubular piston rod may be secured to a fixed member 78 of the seat structure by means of a pair of cooperating nuts 80.V FIG. l also shows how the outer end of the operating rod 34 carries an operating arm S2 that is se-Y cured thereto by a pair of cooperating nuts 84. As best shown in FIG. 2, the opposite end of the kdevice which is the outer end of the cylinder extension 42 is provided with a bushing 85 having an internal screw thread 86 by means of which it may be operatively connected to the backrest of a seat (not shown). The connection is below the pivot axis of the back rest so that the hydraulic locking device is `contracted by any backward tilt movement of the back rest, the relative position of the piston 16 being m'oved rightward as viewed in the drawings to contract the rightward locking chamber 20 in opposition to the resistance of the external counterbalancing spring 22.

To Acause the locking valve ball 24 to be unseated for changing the adjustment of the seat back rest, the operating arm 82 of the operating rod 34 is actuated by suitable manual means which usually includes a push button (not shown) for the convenience of the occupant of the seat. The rotation of the operating rod 34 causes the follower or diametric pin 3S to climb the inclined cammed surfaces of the cam means 36 withconsequent axial shift lof the operating rod towards the right as viewed in the drawings. The rightward shift of the operating rod -34 correspondingly shifts Vthe check'valve member 25 to the right to unseat the-locking valve ball 24 in opposition 5to the coil spring 27.

When the locking valve ball member 24 is unseated,

Vfluid Vmay pass in either direction between the locking chambers 18 and -20 through the previously mentioned radial ports 74, the annular passage 3S around the check valve member 25 and the previously mentioned radial ports 75. It is to be noted that the check valve member 25 has a longitudinally extensive enlarged portion 25a immediately adjacent the O-ring 26 and has a second enlargement 25'b of slightly lesser diameter adjacent the enlargement '25a and directly :opposite the radial ports 74. The hrst enlargement 25a iits into the surrounding structure 'with restricted clearance, the clearance being adequate, however, for ow between the huid reservoir chamber 32 vand the two lockingl chambers but suficiently restricted to prevent any substantial transmission of dynamic pressure into the Ihuid reservoir 32 when the 'check valve lis open. 1 f Y The operating rod -34 is made in two longitudinal sections, one section 34a lbeing connected to the operating arm '82 and having a tubular end portion 34h (Fifi-2) that serves as aV socket for the other section 34C. The tubular end portion 34h serves as a guide for the reservoir spring and its end 140 (FIG. 3) serves as a stop shoulder to limit the retraction of the gland 28 against the reservoir Vspring 3i). l

If the seat is -to be used for daytime plane service, first-class, where the spacing of the seats is intermediate the restricted spacing for coac service and the more extensive spacing for night ilying, the adjustable stop sleeve is manually rotated to the position shown in FIG. 1 to place the diametrically opposite stop shoulders 5t) in alignmentV with the guide slots 40 of the cylinder extension 42. The stop shoulders limit the range of movement of the diametric pin 44 and thereby-limit the extent to which the hydraulic locking device may be contracted for the backward tilt of the seat rest. As shown in FIG. l, the locking sleeve 45 has a knurled or serrated portion 90 to facilitate this adjustment. In like manner, the stop sleeve 45 may be rotated to place the pair of diametrically opposite stop shoulders 43 in the path of the diametrical pin 44 if the seat is to be used for coach service where lesser spacing is provided between the seats; or the locking sleeve may be rotated tothe opposite extreme to place the pair of diametrically opposite shoulders 52 in the path ofthe diametricalV pin 44 when the seat is to be-used for night time flight with maximum spacing between the successive seats. Y

My description in specific detail of the Vselected embodiments of the invention will suggest various changes, substitutions and other departures from my disclosure within the spirit and scope of the appended claims.

I claim:

l. In a locking device to control relative Vmovement between two members, comprising a hydraulic cylinderV connected to one of the two members, a piston rod extending through both ends of said cylinder and connected to the other of the two members, a piston united with said portion rod and dividing'the interior of said cylinder into two locking chambers, and a locking valve controlling fluid flow between the two chambers to control the freedom of movement of said piston, the improvement comprising: longitudinal guide means forming a guide 'i slot extending longitudinally beyond one end of said cylinder; cooperating means carried by the corresponding end of said piston rod in sliding engagement with said slot and guided along a straight pathV thereby to prevent relative rotation between Vthe cylinder and the piston rod; and means to limit the range of movement of said piston rod, said limiting means being adjustable across the .guide 'sl'ot at selected points to block the path of said cooperating means thereby to limit the range of relative movement between thetwo members selectively.

2. In a locking device to control `relative movement between two members, comprising a hydraulic cylinder connected to one of the two members, a piston rod extending through both ends of said cylinder and connected to the other of the two members, a Vpiston united with saidpiston rod and dividing the interior of said cylinder into two locking chambers, and a locking valve controlling uid ow between the two chambers to control the freedom of movement of said piston, the improvement limit the range of relativernovement between said two members selectively.

3. The improvement as set forth in claim 2 which includes detent means effective between said guide means and said rotatable member .to yieldingly hold said rotatable member against rotation at the selected rotary positions thereof.

4. The improvement as set forth in claim 3 in which` said guide means is a cylinderical means with a longitudinal guide slot therein for sliding engagement with said cooperative means carried by the piston rod; and

in which said plurality of stops comprises stop shoulders formed by a longitudinal slot in said rotatable member.

References Cited by the Examiner UNITED STATES PATENTS Hittinger 92-13 Ettenger et al. 92-13 Tetlow 18S-96 Ewing et al. 18S-96 Rothery 92-13 McCormick 82-13 Kehle 18S-96 Porter et al. 188-96 McFadden 18S- 96 Savory 267-8 Porter 188-96 Porter 18S-96 FOREIGN PATENTS 136,813 10/ 20 Great Britain.

10 ARTHUR L. LA POINT, Primary Examiner.

A. JQSEPH GOLDBERG, Examiner. 

1. IN A LOCKING DEVICE TO CONTROL RELATIVE MOVEMENT BETWEEN TWO MEMBERS, COMPRISING A HYDRAULIC CYLINDER CONNECTED TO ONE OF THE TWO MEMBERS, A PISTON ROD EXTENDING THROUGH BOTH ENDS OF SAID CYLINDER AND CONNECTED TO THE OTHER OF THE TWO MEMBERS, A PISTON UNITED WITH SAID PORTION ROD AND DIVIDING THE INTERIOR OF SAID CYLINDER INTO TWO LOCKING CHAMBERS, AND A LOCKING VALVE CONTROLLING FLUID FLOW BETWEEN THE TWO CHAMBERS TO CONTROL THE FREEDOM OF MOVEMENT OF SAID PISTON, THE IMPROVEMENT COMPRISING: LONGITUDINAL GUIDE MEANS FORMING A GUIDE SLOT EXTENDING LONGITUDINALLY BEYOND ONE END OF SAID CYLINDER; COOPERATING MEANS CARRIED BY THE CORRESPONDING END OF SAID PISTON ROD IN SLIDING ENGAGEMENT WITH SAID SLOT AND GUIDED ALONG A STRAIGHT PATH THEREBY TO PREVENT RELATIVE ROTATION BETWEEN THE CYLINDER AND THE PISTON ROD; AND MEANS TO LIMIT THE RANGE OF MOVEMENT OF SAID PISTON ROD, SAID LIMITING MEANS BEING ADJUSTABLE ACROSS THE GUIDE SLOT AT SELECTED POINTS TO BLOCK THE PATH OF SAID COOPERATING MEANS THEREBY TO LIMIT THE RANGE OF RELATIVE MOVEMENT BETWEEN THE TWO MEMBERS SELECTIVELY. 